In an air-conditioning unit system, for example, a space is physically partitioned into areas, one or more indoor units are installed in each area, and the indoor units and outdoor units (hereinafter, the indoor units and the outdoor units will also be referred to as “air-conditioning units”) are controlled so that an environment in each area agrees with a predetermined target. For example, if an air conditioning capacity is insufficient in an arrangement of one indoor unit and one outdoor unit for each area, the number of indoor units and the number of outdoor units are increased to compensate for the insufficient air conditioning capacity.
Some of the systems including a plurality of air-conditioning units perform control based on loads on the air-conditioning units predicted by an empirical rule, any of various programming methods (such as mathematical programming and metaheuristic), or the like in order to reduce the power consumption of the entire system. In such a case, for example, operation points of a plurality of air-conditioning units are programmed on the basis of predicted loads on the air-conditioning units to control the air-conditioning units (see, Patent Literature 1, for example).
Furthermore, there is a method of achieving energy saving by specifying the position of a target which needs air conditioning and by specifying, as a control target group, one or more air-conditioning units that affect the target to efficiently control the air-conditioning units (refer to Patent Literature 2, for example).